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Park TSW, Khan N, Kuo A, Nicholson JR, Corradini L, Smith MT. Characterisation of a rat model of mechanical low back pain at an advanced stage using immunohistochemical methods. Clin Exp Pharmacol Physiol 2021; 48:96-106. [PMID: 32888350 DOI: 10.1111/1440-1681.13402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 07/25/2020] [Accepted: 08/25/2020] [Indexed: 01/23/2023]
Abstract
Chronic low back pain (LBP) has high prevalence in the adult population which is associated with enormous disability. Hence, our aim was to further characterise our LBP rat model by using immunohistological and immunohistochemical methods at an advanced stage (day 49) of the model. Male Sprague-Dawley rats were anaesthetised and their lumbar L4/L5 and L5/L6 intervertebral discs (IVDs) were punctured (0.5 mm outer diameter, 2 mm-deep) 10 times per disc. Sham-rats underwent similar surgery, but no discs were punctured. For LBP- but not sham-rats, noxious pressure hyperalgesia was fully developed in the lumbar axial deep tissues on day 21 post-surgery, which was maintained until at least day 49. In the lumbar (L4-L6) dorsal root ganglia (DRGs), somatostatin (SRIF) and the somatostatin receptor type 4 (SST4 receptor) were co-localised with substance P and IB4, markers of small diameter unmyelinated peptidergic and non-peptidergic C-fibres respectively as well as with NF200, a marker of medium to large diameter neurons. On day 49, there was increased expression of SRIF but not the somatostatin receptor type 4 (SST4 receptor) in the lumbar DRGs and the spinal dorsal horns. There were increased DRG expression levels of the putative pro-nociceptive mediators: phosphorylated p38 (pp38) mitogen-activated protein kinase (MAPK) and phosphorylated p44/p42 MAPK (pp44/pp42 MAPK) as well as pp38 MAPK expression levels in the lumbar spinal cord. Taken together, the increased expression of SRIF in the lumbar DRGs and spinal cord and its co-localisation with nociceptive fibres in DRG sections suggest a potential role of SRIF in modulating chronic mechanical LBP.
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Affiliation(s)
- Thomas S W Park
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
- Department of Neurophysiology, Mannheim Centre for Translational Neuroscience, Heidelberg University, Mannheim, Germany
| | - Nemat Khan
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Andy Kuo
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | | | - Laura Corradini
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Maree T Smith
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
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Merighi A. The histology, physiology, neurochemistry and circuitry of the substantia gelatinosa Rolandi (lamina II) in mammalian spinal cord. Prog Neurobiol 2018; 169:91-134. [PMID: 29981393 DOI: 10.1016/j.pneurobio.2018.06.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 06/07/2018] [Accepted: 06/30/2018] [Indexed: 02/06/2023]
Abstract
The substantia gelatinosa Rolandi (SGR) was first described about two centuries ago. In the following decades an enormous amount of information has permitted us to understand - at least in part - its role in the initial processing of pain and itch. Here, I will first provide a comprehensive picture of the histology, physiology, and neurochemistry of the normal SGR. Then, I will analytically discuss the SGR circuits that have been directly demonstrated or deductively envisaged in the course of the intensive research on this area of the spinal cord, with particular emphasis on the pathways connecting the primary afferent fibers and the intrinsic neurons. The perspective existence of neurochemically-defined sets of primary afferent neurons giving rise to these circuits will be also discussed, with the proposition that a cross-talk between different subsets of peptidergic fibers may be the structural and functional substrate of additional gating mechanisms in SGR. Finally, I highlight the role played by slow acting high molecular weight modulators in these gating mechanisms.
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Affiliation(s)
- Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095 Grugliasco (TO), Italy.
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Shenoy PA, Kuo A, Khan N, Gorham L, Nicholson JR, Corradini L, Vetter I, Smith MT. The Somatostatin Receptor-4 Agonist J-2156 Alleviates Mechanical Hypersensitivity in a Rat Model of Breast Cancer Induced Bone Pain. Front Pharmacol 2018; 9:495. [PMID: 29867498 PMCID: PMC5962878 DOI: 10.3389/fphar.2018.00495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 04/25/2018] [Indexed: 12/12/2022] Open
Abstract
In the majority of patients with breast cancer in the advanced stages, skeletal metastases are common, which may cause excruciating pain. Currently available drug treatments for relief of breast cancer-induced bone pain (BCIBP) include non-steroidal anti-inflammatory drugs and strong opioid analgesics along with inhibitors of osteoclast activity such as bisphosphonates and monoclonal antibodies such as denosumab. However, these medications often lack efficacy and/or they may produce serious dose-limiting side effects. In the present study, we show that J-2156, a somatostatin receptor type 4 (SST4 receptor) selective agonist, reverses pain-like behaviors in a rat model of BCIBP induced by unilateral intra-tibial injection of Walker 256 breast cancer cells. Following intraperitoneal administration, the ED50 of J-2156 for the relief of mechanical allodynia and mechanical hyperalgesia in the ipsilateral hindpaws was 3.7 and 8.0 mg/kg, respectively. Importantly, the vast majority of somatosensory neurons in the dorsal root ganglia including small diameter C-fibers and medium-large diameter fibers, that play a crucial role in cancer pain hypersensitivities, expressed the SST4 receptor. J-2156 mediated pain relief in BCIBP-rats was confirmed by observations of a reduction in the levels of phosphorylated extracellular signal-regulated kinase (pERK), a protein essential for central sensitization and persistent pain, in the spinal dorsal horn. Our results demonstrate the potential of the SST4 receptor as a pharmacological target for relief of BCIBP and we anticipate the present work to be a starting point for further mechanism-based studies.
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Affiliation(s)
- Priyank A Shenoy
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Andy Kuo
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Nemat Khan
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Louise Gorham
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Janet R Nicholson
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Laura Corradini
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.,Faculty of Health and Behavioural Sciences, School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
| | - Maree T Smith
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia.,Faculty of Health and Behavioural Sciences, School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
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Shi TJS, Xiang Q, Zhang MD, Barde S, Kai-Larsen Y, Fried K, Josephson A, Glück L, Deyev SM, Zvyagin AV, Schulz S, Hökfelt T. Somatostatin and its 2A receptor in dorsal root ganglia and dorsal horn of mouse and human: expression, trafficking and possible role in pain. Mol Pain 2014; 10:12. [PMID: 24521084 PMCID: PMC3943448 DOI: 10.1186/1744-8069-10-12] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 02/06/2014] [Indexed: 12/30/2022] Open
Abstract
Background Somatostatin (SST) and some of its receptor subtypes have been implicated in pain signaling at the spinal level. In this study we have investigated the role of SST and its sst2A receptor (sst2A) in dorsal root ganglia (DRGs) and spinal cord. Results SST and sst2A protein and sst2 transcript were found in both mouse and human DRGs, sst2A-immunoreactive (IR) cell bodies and processes in lamina II in mouse and human spinal dorsal horn, and sst2A-IR nerve terminals in mouse skin. The receptor protein was associated with the cell membrane. Following peripheral nerve injury sst2A-like immunoreactivity (LI) was decreased, and SST-LI increased in DRGs. sst2A-LI accumulated on the proximal and, more strongly, on the distal side of a sciatic nerve ligation. Fluorescence-labeled SST administered to a hind paw was internalized and retrogradely transported, indicating that a SST-sst2A complex may represent a retrograde signal. Internalization of sst2A was seen in DRG neurons after systemic treatment with the sst2 agonist octreotide (Oct), and in dorsal horn and DRG neurons after intrathecal administration. Some DRG neurons co-expressed sst2A and the neuropeptide Y Y1 receptor on the cell membrane, and systemic Oct caused co-internalization, hypothetically a sign of receptor heterodimerization. Oct treatment attenuated the reduction of pain threshold in a neuropathic pain model, in parallel suppressing the activation of p38 MAPK in the DRGs Conclusions The findings highlight a significant and complex role of the SST system in pain signaling. The fact that the sst2A system is found also in human DRGs and spinal cord, suggests that sst2A may represent a potential pharmacologic target for treatment of neuropathic pain.
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Affiliation(s)
- Tie-Jun Sten Shi
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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Zhang WB, Zhao Y, Kjell F. Understanding propagated sensation along meridians by volume transmission in peripheral tissue. Chin J Integr Med 2013; 19:330-9. [PMID: 23674110 DOI: 10.1007/s11655-013-1456-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Indexed: 02/03/2023]
Abstract
Propagated sensation along meridians (PSM) is a phenomenon that a sensation moves along meridians during stimulation of an acupoint. PSM has an appearance rate of 1.3% among people and have characteristics of low speed, going toward afflicted sites and being blocked by physical pressure which is difficult to be explained by known neural and blood transmission. Volume transmission (VT) is a widespread mode of intercellular communication in the central nervous system that occurs in the extracellular fluid and in the cerebrospinal fluid. VT signals moves from source to target cells via energy gradients leading to diffusion and convection (flow) which is slow, long distance and much less space filling. VT channel diffuse forming a plexus in the extracellular space with two parameters of volume fraction and tortuosity. Some experiments showed an information transmission between adjacent and distant acupoints along meridians cross spinal segments. This process is a cross-excitation between peripheral nerve terminals which is related to nonsynaptic transmission. Some neurotransmitters or neuropeptides such as glutamate, adenosine triphosphate (ATP) and neuropeptide such as substance P, neurokinin A and calcitonin gene-related peptide relate with the cross-excitation which can be regards as VT signals. Comparing the characteristics of PSM and VT, many similar aspects can be found leading to an assumption that PSM is a process of VT in peripheral tissue along meridians. The reason why VT signals transmit along meridians is that the meridian is rich in interstitial fluid under the condition of low hydraulic resistance which has been proven experimentally. According to Darcy's law which descript the flow of interstitial fluid and conservation equation, interstitial fluid will move toward meridians and flow along meridians that restrict the VT signals within the channel and accelerate the flow according to Fick's diffusion law. During the process, a degranulation of histamine from mast cells happens on the route which can expand capillary and increase the blood perfusion and interstitial fluid which had already been observed. The mechanism of PSM is featured by alternative axon reflex (wired transmission, WT) and VT in peripheral tissue along meridians, sending simultaneously a continuous sensate signal to control nerve system which can be felt like a PSM.
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Affiliation(s)
- Wei-Bo Zhang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Science, Beijing 100700, China.
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Ionov ID, Pushinskaya II. Somatostatin antagonist induces catalepsy in the aged rat. Psychopharmacology (Berl) 2013; 227:273-6. [PMID: 23274508 DOI: 10.1007/s00213-012-2961-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/14/2012] [Indexed: 02/02/2023]
Abstract
RATIONALE Extrapyramidal motor signs are the major features of Parkinson's disease (PD). It is unclear whether there is a link between these signs and such PD-associated factors as brain somatostatin deficiency and aging. OBJECTIVES This study aimed to examine whether an inhibition of the brain somatostatin system can initiate catalepsy, a model of extrapyramidal disorders, in young and aged rats. METHODS The animals of 100-110 and 540-560 days of age were used. Catalepsy was measured using the bar test. The inhibition of the brain somatostatin activity was simulated by intracerebroventricular administration of a somatostatin antagonist, cyclosomatostatin. RESULTS Cyclosomatostatin dose-dependently induced catalepsy in aged, but not in young rats. The cataleptic response was reversed by a somatostatin analog, octreotide. CONCLUSIONS The combination of aging and brain somatostatin deficiency can lead to catalepsy in rats. Since both factors are frequently observed in PD patients, the present results might be of relevance for pathogenesis of extrapyramidal signs in this disease.
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Affiliation(s)
- Ilya D Ionov
- Centre on Theoretical Problems in Physical and Chemical Pharmacology, Russian Academy of Sciences, Leninsky Prospect 123-4-63, Moscow, 117513, Russia.
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Somatostatin antagonist potentiates haloperidol-induced catalepsy in the aged rat. Pharmacol Biochem Behav 2012; 103:295-8. [DOI: 10.1016/j.pbb.2012.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 08/02/2012] [Accepted: 08/11/2012] [Indexed: 11/18/2022]
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Wang J, Cao DY, Guo Y, Ma SJ, Luo R, Pickar JG, Zhao Y. Octreotide inhibits capsaicin-induced activation of C and Aδ afferent fibres in rat hairy skin in vivo. Clin Exp Pharmacol Physiol 2012; 38:521-7. [PMID: 21595740 DOI: 10.1111/j.1440-1681.2011.05542.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
1. The present study investigated whether the somatostatin receptor (SSTR) agonist, octreotide, could inhibit the activation of dorsal skin afferent fibres induced by local injection of capsaicin in the rat. 2. Single unit activity from Aδ mechano-heat sensitive (AMH; n = 41) and C mechano-heat sensitive (CMH; n = 30) afferents was recorded after their isolation in thin filaments from the dorsal cutaneous nerve branches. The effect of subcutaneous octreotide injection on the change in discharge rate and mechanical threshold induced by capsaicin was determined. 3. Capsaicin (0.05%) injection into the edge of the receptive field of both AMH and CMH units increased their discharge rate and decreased their mechanical threshold. Pre-injection of octreotide inhibited these responses, and co-application of SSTR antagonist, cyclosomatostatin, reversed the inhibitory effect of octreotide. 4. The present study provides electrophysiological evidence that the signal evoked by the somatostatin receptor inhibits the activation and mechanical sensitization evoked by capsaicin in the terminals in small-diameter sensory neurons.
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Affiliation(s)
- Jun Wang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Medicine, Shaanxi, China
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Luo R, Guo Y, Cao DY, Pickar JG, Li L, Wang J, Zhao Y. Local effects of octreotide on glutamate-evoked activation of Aδ and C afferent fibers in rat hairy skin. Brain Res 2010; 1322:50-8. [DOI: 10.1016/j.brainres.2010.01.058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 01/19/2010] [Accepted: 01/22/2010] [Indexed: 10/19/2022]
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